1. Field of the Invention
This invention relates to a universal joint for transmitting rotational forces between two members. One potential application for this universal joint is in the field of musical instruments, more specifically, to a drum pedal linkage system, although the joint may be used in myriad other fields.
2. Background of the Invention
Universal joints have multiple uses in applications where rotational forces from a first shaft are transferred to a second shaft.
U.S. Pat. No. 7,633,000 to Dorfman, et al., discloses a universal joint that can be used in several areas and that has particular applicability to a drum pedal linkage, whereby a user seeks to actuate a drum beater by depressing a pedal remotely located from the beater but operatively connected via a rotating linkage. The universal joint in this patent includes a spider formed as a unitary member. The spider is operatively coupled to a plurality of yokes via a plurality of trunnions that are held in place with needle bearings, bushings, etc. While this universal joint features significant anti-backlash advantages over other universal joints, the use of needle bearings may introduce sizing variations that require the manufacture and use of trunnions of multiple sizes, which may increase cost and require longer assembly times.
U.S. Pat. No. 6,878,068 to Bigelow, et al., discloses a multi-piece universal joint that also uses needle bearings. In addition, while Bigelow teaches the use of a multi-piece ring member, it disparages the use of “split rings” as allegedly reducing bearing strength and requiring removal of both shafts in order to install and/or service the joints.
U.S. Pat. No. 2,336,579 to Venditty, et al., discloses a universal joint that similarly relies on the use of needle bearings. It incorporates a cushioning assembly around each bearing, which, while reducing or eliminating a need to seal the bearing, also may allow for lateral displacement of the yoke members and/or the bearings themselves.
U.S. Pat. No. 1,273,289 to Urschel discloses a universal joint that uses bushings, not bearings, to aid in rotational movement. The halves of the ring in the Urschel joint are joined by rivets, which still may permit lateral movement of the yokes, introducing backlash and inefficiency into the joint.
What is needed is a universal joint that overcomes the drawbacks described above.